Year	% of total
1960	0
1961	0
1962	0
1963	0.0062340253101427585
1964	0.005693139766581269
1965	0.010312467773538208
1966	0.018870594895504078
1967	0.008476731372382808
1968	0.003774297037176826
1969	0.13247539742619227
1970	0.14112334180073383
1971	0.6354724723583722
1972	1.1226579685959188
1973	1.3901673393282825
1974	1.1965522353289988
1975	1.3990108004441306
1976	1.670485623475497
1977	1.568649499606432
1978	1.541838134430727
1979	1.722400201576617
1980	1.8556419702551508
1981	2.128148881969997
1982	2.2832884944621084
1983	2.4611584449058492
1984	2.4071514146161643
1985	2.6768956028937443
1986	2.6395333166477353
1987	2.8759149328568956
1988	3.7750796838439857
1989	4.469861196492704
1990	5.293632220258581
1991	5.770891949057198
1992	5.768332329662766
1993	6.030685892439594
1994	6.31283857130351
1995	7.3513762573780035
1996	8.602549326379835
1997	10.417932102489843
1998	10.377572789009445
1999	10.936042542488591
2000	11.884525587262623
2001	12.74164015061569
2002	13.73234340527578
2003	15.347636666039039
2004	17.1810030992967
2005	19.501534950071328
2006	20.930375095090408
2007	20.523744502086387
2008	24.665371421520234
2009	24.875242269296326
2010	26.09239926806953
2011	24.15221975218659
2012	24.304582389423253
2013	24.679755766062602
2014	22.494159611553783
2015	21.929312470735134
2016	23.2150803546128